DECOUPLED OUTPUT VOLTAGE CONTROL OF QUANTUM SERIES RESONANT CONVERTERFOR IMPROVED BUCK-BOOST OPERATION

A new output voltage control technique is proposed to obtain the impro ved buck-boost operation of the quantum series resonant converter (QSR C), The new nonlinear dynamic model of QSRC is first derived and the c ross-coupled nonlinear term existing in the output voltage dynamics is decoupled by using control methods such as the periodic control of th e boosting switch (PCBS) and the resonant current control (RCC), By ap plying the state space averaging concept to the decoupled dynamics, tw o linear large signal averaged models are obtained for PCBS-and RCC sc hemes. Using the proposed technique, the flux imbalance problem of the isolation transformer and the robustness of the output voltage respon se can be easily considered, This technique can also be widely applica ble to the cascade buck-boost converter, which can be implemented by i nserting a boosting switch between the output filter inductor and the ripple capacitor of the forward converter, The validity of the propose d scheme is confirmed by the computer simulations and the experiments.